Image reader

ABSTRACT

An image reader includes: a document transport path through which a document to be read is transported; a transport roller that is provided on a lower side in the document transport path and is driven to apply a feed force to the document. The lower side of the document transport path upstream from the transport roller is at a position that is lower than a highest position of an outer circumferential surface of the transport roller and is formed on a lower guide surface guiding the document to the transport roller. A guiding unit is provided downstream from the lower guide surface and guides the document from the lower guide surface to a position on the outer circumferential surface of the transport roller, the position being higher than the lower guide surface.

The present application is based on, and claims priority from JP Application Serial Number 2018-087123, filed Apr. 27, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to an image reader that reads a document.

2. Related Art

JP-A-2015-050582 discloses a reading apparatus as an example of an image reader. The reading apparatus has a configuration in which a document holder is provided at a position opposite to an image sensor and a reading position is set between the image sensor and the document holder.

In the configuration disclosed in JP-A-2015-050582, the image sensor is provided on a lower side, and thus a document is fed and discharged in a face-down state. Conversely, a configuration in which it is possible to check content of a document, that is, a configuration in which the document is fed and discharged in a face-up state, is referred to as a configuration that is easy for a user to use.

In this case, in contrast to JP-A-2015-050582, a document holder is disposed on a lower side, and an image sensor is disposed on an upper side. However, when the document holder is configured of a roller, there is a concern that a leading end of a document, which moves toward a nip position between the roller and the image sensor, will come into belly contact with the roller, and abnormal transport due to inappropriate nipping will occur.

SUMMARY

An advantage of some aspects of the disclosure is to suppress belly contact of a leading end of a document to a roller disposed on a lower side of a document transport path so as to realize appropriate transport of the document.

The present disclosure is made to provide an image reader.

According to an aspect of the present disclosure, an image reader includes: a document transport path through which a document to be read is transported; a transport roller that is provided on a lower side in the document transport path and is driven to apply a feed force to the document; and a document holding unit that is provided above the transport roller and holds the document in cooperation with the transport roller. The lower side of the document transport path upstream from the transport roller is at a position that is lower than a highest position of an outer circumferential surface of the transport roller and is formed on a lower guide surface guiding the document to the transport roller. A guiding unit is provided downstream from the lower guide surface and guides the document from the lower guide surface to a position on the outer circumferential surface of the transport roller, the position being higher than the lower guide surface.

In this configuration, the lower guide surface that guides the document to the transport roller is formed on the lower side of the document transport path upstream from the transport roller at the position that is lower than the highest position of an outer circumferential surface of the transport roller, and the guiding unit is provided downstream from the lower guide surface and guides the document from the lower guide surface to the position on the outer circumferential surface of the transport roller, the position being higher than the lower guide surface. Therefore, a leading end of the document inserted into the document transport path is guided to the high position, and thereby it is possible to suppress belly contact of the leading end of the document with the transport roller such that it is possible to realize appropriate transport.

In the image reader, the guiding unit may be configured to switch between a first state in which the document is guided to the position on the outer circumferential surface of the transport roller, the position being higher than the lower guide surface, and a second state in which the document is guided to a position that is lower than the position to which the document is guided in the first state.

In this configuration, the guiding unit is configured to switch between the first state in which the document is guided to the position on the outer circumferential surface of the transport roller, the position being higher than the lower guide surface, and the second state in which the document is guided to the position that is lower than the position to which the document is guided in the first state. Therefore, in the second state, when the document is inserted into the document transport path such that the leading end of the document comes into abutting contact with the transport roller, it is possible to obtain a strong feeling of contact.

In this configuration, when the leading end is guided to the high position on the outer circumferential surface of the transport roller, there is a lack of the feeling of bump contact, and thus the leading end of the document may be inserted to a deeper side than a document nipping position by the transport roller and the document holding unit, depending on types of originals (particularly, when the document has high stiffness). However, the guiding unit comes into the second state, and thereby it is possible to position the documents at appropriate standby positions, respectively.

An increase in feeling of bump contact of the leading end of the document with the transport roller means that the leading end of the document comes into belly contact with the transport roller. However, even when the leading end comes into belly contact with the transport roller, the leading end is appropriately guided to a space between the transport roller and the document holding unit by rotation of the transport roller, depending on types of originals (particularly, when the document has high stiffness). The image reader according to the disclosure is suitable for reading both the documents and a document that is likely to cause abnormal transport due to the belly contact with the transport roller.

In the image reader, the guiding unit may maintain the first state by a pressing force of a pressing unit in a non-transport state of the document, and the guiding unit may maintain the first state when a first medium is inserted into the document transport path and performs switching from the first state to the second state when a second medium that is thicker than the first medium is inserted into the document transport path.

In this configuration, the guiding unit switches between the first state and the second state depending on the thickness of the document. Therefore, there is no need to provide a dedicated unit that switches a state of the guiding unit, and thus it is possible to suppress an increase in cost of the reader.

In the image reader, the guiding unit may come into a non-projection state from the lower guide surface in the second state.

According to the image reader, the guiding unit comes into the non-projection state from the lower guide surface in the second state. Therefore, it is possible to more smoothly obtain the feeling of bump contact of the leading end of the document with the transport roller.

In the image reader, the guiding unit may be formed to have a size to cover the entire length along a document width direction that is a direction intersecting a document transport direction.

In this configuration, the guiding unit may be formed to have the size to cover the entire length in a document width direction that is the direction intersecting the document transport direction. Therefore, regardless of a size of the document, it is possible to guide the leading end of the document inserted into the document transport path to the high position, and it is possible to more reliably suppress the belly contact of the leading end of the document with the transport roller such that it is possible to realize the appropriate transport.

In the image reader, the document holding unit that nips the document in cooperation with the transport roller may be a sensor unit of which a surface that is brought into contact with the transport roller is configured of a reading surface and which reads the document, and the sensor unit may be configured to move toward and back from the transport roller.

In this configuration, the document holding unit that nips the document in cooperation with the transport roller is the sensor unit of which the surface that is brought into contact with the transport roller is configured of the reading surface and which reads the document. Therefore, the document holding unit is configured of the sensor unit, and thereby it is possible to contribute to a reduction in cost and size of the reader. In addition, the sensor unit is configured to move toward and back from the transport roller, and thus it is possible to read originals having various thicknesses.

In the image reader, the document transport path may be extended along a horizontal direction when the reader has a first posture and may include a rotation-contact member that is provided upstream from the transport roller in the document transport path and rotates to have a posture in which a contact portion that comes into contact with the document blocks the document transport path and a posture in which the contact portion opens the document transport path, a pressing member that presses the rotation-contact member in a direction in which the contact portion blocks the document transport path, and a detecting unit that detects the posture of the rotation-contact member. A rotation center of the rotation-contact member is positioned on an upper side of the document transport path in the first posture and the contact portion projects from the upper side toward the lower side of the document transport path. A center-of-gravity position of the rotation-contact member is on a lower side from the rotation center in the first posture.

In this configuration, the first posture is one of the postures of the reader and means a posture in which the document transport path is extended along the horizontal direction, a posture that can be taken for a longest time of a service life of the reader, and a normal installation posture. The image reader according to the disclosure uses such features described above. In other words, the rotation-contact member, with which the leading end of the document comes into contact such that the rotation-contact member rotates, is positioned on the upper side of the document transport path, the contact portion projects from the upper side toward the lower side of the document transport path, and the center-of-gravity position of the rotation-contact member is on the lower side from the rotation center in the first posture. Therefore, the rotation-contact member can be lowered by its own weight without a need of the pressing force of the pressing unit and block the document transport path.

In this configuration, in the first posture, that is, the posture that is highly likely to be taken for the longest time of the service life of the reader, it is possible to appropriately maintain the posture of the rotation-contact member in which the pressing force of the pressing unit does not act against a force by which the rotation-contact member retracts from the document transport path due to action of gravity. In addition, an unnecessary opposite force does not act on the pressing unit in the first posture, and thus it is possible to appropriately maintain the pressing force of the pressing unit over a long period.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external perspective view illustrating a scanner according to the present disclosure.

FIG. 2 is an external perspective view illustrating the scanner according to the present disclosure.

FIG. 3 is an external perspective view illustrating a state in which upper and lower housings are removed from the scanner according to the present disclosure.

FIG. 4 is an external perspective view illustrating a state in which the upper housing is removed from the scanner according to the present disclosure.

FIG. 5 is an external perspective view illustrating a state in which the upper and lower housings are removed from the scanner according to the present disclosure.

FIG. 6 is a sectional side view illustrating a document transport path in the scanner according to the present disclosure.

FIG. 7 is a perspective view of a partial cross section of the scanner according to the present disclosure.

FIG. 8 is a perspective view of a partial cross section of the scanner according to the present disclosure.

FIG. 9 is a view illustrating a state of an guiding unit when a thin original is inserted.

FIG. 10 is a view illustrating a state of the guiding unit when a thick original is inserted.

FIG. 11 is a view illustrating a path forming member and the guiding unit entirely.

FIG. 12 is an overall perspective view of a document detecting lever.

FIG. 13 is a diagram illustrating a force acting on the document detecting lever when an apparatus is placed in a horizontal posture (first posture).

FIG. 14 is a diagram illustrating a force acting on the document detecting lever when the apparatus is placed in a vertical posture (second posture).

FIG. 15 is a perspective view illustrating one side surface of the scanner according to the present disclosure.

FIG. 16 is a perspective view illustrating an inner side of the upper housing.

FIG. 17 is a perspective view of a top frame.

FIG. 18 is a sectional side view of a scanner according to another embodiment.

FIG. 19 is a flowchart illustrating control when the document is inserted.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of an image reader according to the present disclosure will be described with reference to the drawings. In this embodiment, an example of the image reader includes a handy scanner that is configured to read one of a front surface and a back surface of a document.

In the drawings, an X direction in an X-Y-Z coordinate system is an apparatus width direction or a document width direction that is a direction intersecting a document transport direction. In addition, a Y direction is the document transport direction. A Z direction is a perpendicular direction and an apparatus height direction. In addition, a +Y direction side is set as a document discharge direction, a right side and a left side are set as a +X direction and −X direction, respectively, when a document insertion opening 5 is in front.

In addition, a +Z direction is set as a vertically upward direction, and a −Z direction side is set as a vertically downward direction. In addition, a direction (+Y direction side), in which the document is transported, is referred to as “downstream”, and an opposite direction (−Y direction side) thereof is referred to as “upstream”.

A scanner 1 according to the embodiment is small and is a so-called handy scanner. Hence, an apparatus posture when an apparatus is used is not necessarily limited to a state illustrated in FIGS. 1 and 2, that is, a top surface (operation panel 7) of the apparatus is oriented toward the vertically upward direction and a document transport path T to be described below is disposed along a horizontal direction. However, unless particularly described hereinafter, a case where structures, positional relationships, or the like of configurational elements are described by words of an “upper side”, a “lower side”, or the like is described on a premise of a case where the apparatus is placed in a posture (normal posture) illustrated in FIGS. 1 and 2.

In FIGS. 1 and 2, the scanner 1 has an elongated shape along the X direction and has an external appearance that is substantially configured of an upper housing 4, an operation panel 7, and a lower housing 3. The operation panel 7 for performing various operations is provided on the +X direction side. A connector inserting opening 14 for coupling to an external device is open in a side surface on a side of the operation panel 7.

As illustrated in FIG. 1 in which the document insertion opening 5 is disposed in front, the document insertion opening 5 is formed between a path forming member 9 and a top frame 8.

In addition, as illustrated in FIG. 2 in which a document discharge opening 6 is disposed in front, the document discharge opening 6 is formed between the upper housing 4 and the lower housing 3, and a part of a transport roller 11 to be described below is viewed on an inner side of the document discharge opening 6.

As illustrated in FIGS. 3 and 5 in which the upper housing 4 and the lower housing 3 are removed and FIG. 4 in which only the upper housing 4 is removed, an apparatus main body 2 of the scanner 1 is configured of a base body including the path forming member 9, which forms a lower side of the document transport path, and the top frame 8 and a sensor unit 20 which form an upper side of the document transport path. On the upper side of the document transport path, the top frame 8 forms a part of the document transport path which is formed upstream, and the sensor unit 20 forms a part of the document transport path which is formed downstream.

On the lower side from the path forming member 9, a battery 17 and a control unit 16 are provided as illustrated in FIG. 5 and configure a bottom portion of the apparatus main body 2. The control unit 16 has a configuration in which a plurality of electronic components are provided on a circuit board.

On a −X direction side of the apparatus main body 2, a motor 18 is provided and has a configuration in which power of the motor 18 is transmitted to the transport roller 11 as a drive roller to be described below.

A dashed line represented by a reference sign T in FIG. 6 denotes the document transport path, and the document transport path T is disposed substantially along the horizontal direction in a normal posture of the scanner 1.

A document that is inserted from the document insertion opening 5 is moved toward a nip position by the transport roller 11 and the sensor unit 20 as an “original holding unit” while being guided by the path forming member 9. A user who uses the scanner 1 can obtain a feeling of bump contact feeling when the document is inserted from the document insertion opening 5 and a leading end of the document bumps against the nip position by the transport roller 11 and the sensor unit 20 or the leading end of the document bumps against the transport roller 11. In a manual mode, the leading end of the document is slightly nipped between the transport roller 11 and the sensor unit 20 through slight rotation of the transport roller 11. In this state (reading standby state), a scan button 7 a (FIGS. 1 to 4) is pressed down, and thereby rotation of the transport roller 11 is started, and reading of the document is started. In an automatic mode, transport and reading of the document are automatically performed without pressing down of the scan button 7 a, and this will be described below.

As illustrated in FIG. 6, a document detecting lever 10 is provided between the document insertion opening 5 and the transport roller 11. The document detecting lever 10 is provided to be rotatable around a rotary shaft 10 a (also refer to FIG. 12) with respect to the top frame 8 in a side view of the document transport path T. The rotary shaft 10 a is positioned on the upper side from the document transport path T, and a contact portion 10 b is provided to project from the rotary shaft 10 a to the document transport path T from the upper side to the lower side so as to block the document transport path T.

A coil spring 12 as an example of a pressing unit is provided on the rotary shaft 10 a of the document detecting lever 10 and presses the document detecting lever 10 in a direction (clockwise direction in FIG. 6) in which the contact portion 10 b projects to the document transport path T.

The document detecting lever 10 is provided with a detection target portion 10 d (FIG. 12), and the detection target portion 10 d blocks an optical axis of a sensor 13 (FIGS. 3 and 4), which is an optical sensor provided on the top frame 8, or is moved away from the optical axis, by rotation of the document detecting lever 10.

When the document is inserted from the document insertion opening 5, the leading end of the document pushes up the contact portion 10 b, and the document detecting lever 10 rotates as illustrated by a reference sign 10-1. In other words, the document detecting lever 10 rotates to have a posture in which the contact portion 10 b that comes into contact with the document blocks the document transport path T and a posture in which the contact portion 10 b opens the document transport path T.

In the configuration described above, the control unit 16 (FIG. 5) of the scanner 1 can detect whether or not the document is inserted into the document transport path T based on a detection signal that is transmitted from the sensor 13 as an example of a detecting unit that detects the posture of the document detecting lever 10.

The document detecting lever 10 is provided with the contact portions 10 b and recessed portions 10 c which are alternately formed in a longitudinal direction (X direction) as illustrated in FIG. 12. On the other hand, the path forming member 9 is provided with recessed portions 9 a at predetermined intervals along the X direction (FIG. 11), and the contact portions 10 b enter the recessed portions 9 a. In this manner, the contact portions 10 b can block the document transport path T.

Next, in the embodiment, the sensor unit 20 is configured as a contact image sensor module (CISM) and includes a glass plate 21 that forms a reading surface 21 a on the lower side from a frame 22 that configures the base body.

The sensor unit 20 is provided to be displaced along a vertical direction so as to perform nipping originals having various thicknesses such that the document is nipped between the glass plate 21 and the transport roller 11.

As illustrated in FIG. 7, an end portion of the upper housing 4 in the +X direction is provided with a guide groove 4 d that is extended along the vertical direction and has a configuration in which protrusions 22 a and 22 a formed on the frame 22 that configures the sensor unit 20 enter the guide groove 4 d and are guided along the vertical direction.

In addition, as illustrated in FIG. 8, an end portion of the upper housing 4 in the −X direction is provided with a guide groove 4 b that is extended along the vertical direction and has a configuration in which protrusions 22 a and 22 b formed on the frame 22 that configures the sensor unit 20 enter the guide groove 4 b and are guided along the vertical direction.

The protrusion 22 b illustrated in FIG. 8 has a diameter that is slightly smaller than a diameter of the protrusion 22 a, and a certain size of play space is secured between the guide groove 4 b and the protrusion 22 b. Consequently, while a posture of the sensor unit 20 is stabilized, smooth displacement of the sensor unit 20 along the vertical direction is more secured than in a configuration in which all of the protrusions are formed to have the same diameter.

A circuit board 23 is provided on a top surface of the sensor unit 20 as illustrated in FIGS. 3, 4, and 6, and springs 19 that exert a pressing force are provided between the circuit board 23 and the upper housing 4. In the embodiment, two springs 19 are compression springs and are provided at an interval along the X direction. The sensor unit 20 is pressed by the spring 19 in a downward direction, and thus the glass plate 21 comes into press contact with the transport roller 11.

Here, a position Y1 in FIG. 6 is a rotation center position of the transport roller 11 and also a contact center position with the glass plate 21. In addition, a position Y2 is a reading position of the sensor unit 20. As illustrated in FIG. 6, the position Y2 is positioned slightly deeper on an inner side (upstream) in the apparatus than the position Y1. Consequently, deterioration of reading quality due to an influence of external light entering the inside of the apparatus from the document discharge opening 6 is suppressed.

The transport roller 11 is formed by providing an elastic material (for example, elastomer) on an outer circumferential surface of a metal shaft. Hence, the elastic material is crushed in a contact part of the transport roller with the glass plate 21, and thus a contact region between the transport roller 11 and the glass plate 21 has a predetermined length (for example, about 1 mm) in the document transport direction. The reading position Y2 is positioned in the contact region between the transport roller 11 and the glass plate 21, the contact region being formed due to crushing of the transport roller 11.

Subsequently, a guiding unit provided in an upstream portion from the transport roller 11 will be described with reference to FIGS. 9 and 10. In the scanner 1 according to the embodiment, the document is transported and discharged in a face-up state such that the sensor unit 20 is disposed on the upper side of the document transport path T. Therefore, the scanner has a configuration in which it is possible to insert the document while content of the document is checked and which is easy for the user to use. Additionally, there is no need to provide a roller that is paired with the transport roller 11, and thus it is possible to achieve a reduction in cost of the apparatus. However, in the configuration, there is a concern that abnormal transport will occur without appropriate nipping of the document when the leading end of the document, which moves toward the nip position between the transport roller 11 and the sensor unit 20, comes into belly contact with the transport roller 11 and the user takes his/her hand off depending on a feeling of bump contact which is aroused in such a case.

In other words, a lower guide surface 9 b that is the lower side of the document transport path T, that is, a top surface of the path forming member 9, is provided upstream from the transport roller 11 that is provided on the lower side in the document transport path T and is driven to apply a feed force to the document. A height position (position HO) of the lower guide surface 9 b is lower than a highest position (position H2) of an outer circumferential surface of the transport roller 11. In such a configuration, there is a concern that the leading end of the document will come into belly contact with the transport roller 11.

In the scanner 1, an guiding unit 30 is provided downstream from the lower guide surface 9 b and guides the document from the lower guide surface 9 b to a position (for example, a position H1) on the outer circumferential surface of the transport roller 11, the position being higher than the lower guide surface 9 b. Consequently, the leading end of the document inserted into the document transport path T is guided to the high position H1 as illustrated in a process from the top to bottom figures in FIG. 9, and thereby it is possible to suppress belly contact of the leading end of the document with the transport roller 11 so as to realize appropriate transport.

The top surface of the guiding unit 30 is a guiding surface that guides the leading end of the document to the high position. However, it is possible to appropriately set an inclination angle of the guiding surface when the leading end of the document is guided to the high position. For example, the guiding surface may be continuous to a tangential line on the outer circumferential surface of the transport roller 11 in a side view of the document transport path T.

In addition, in the embodiment, the guiding unit 30 is configured to switch between a first state (the top figure in FIG. 9) in which the document is guided to the position H1 on the outer circumferential surface of the transport roller 11, the position H1 being higher than the lower guide surface 9 b, and a second state (the bottom figure in FIG. 10) in which the document is guided to a position H0 that is lower than the position H1 to which the document is guided in the first state.

Hereinafter, to be further described, the guiding unit 30 is provided to be rotatable around a rotary shaft 30 a in a side view of the document transport path T, is pressed in an upward direction by a coil spring 31 as an example of a pressing unit, and maintains the first state. The guiding unit 30 is configured to stop rotation in an upward posture by a stopper not illustrated, as illustrated in top figures of FIGS. 9 and 10.

FIG. 9 is a view for describing movement of the guiding unit 30 when a thin original P1 such as plain paper having relatively low stiffness is inserted. When a leading end P1 a of the document P1 reaches the guiding unit 30 as illustrated in the process from the top to bottom figures of FIG. 9, the leading end P1 a is guided to the position H1 higher than the position H0 (height position of the lower guide surface 9 b) by the guiding unit 30 maintained in the first state. Consequently, the belly contact of the leading end P1 a with the transport roller 11 is suppressed.

On the other hand, FIG. 10 is a view for describing movement of the guiding unit 30 when a thick original P2 such as a credit card or a cash card having high stiffness is inserted. When a leading end P2 a of the document P2 reaches the guiding unit 30 as illustrated in a process from the top to bottom figures of FIG. 10, the document P2 pushes down the guiding unit 30, and thereby a lower corner of the leading end P2 a comes into abutting contact with the outer circumferential surface of the transport roller 11 at the same height position substantially as the position H0 (height position of the lower guide surface 9 b). The guiding unit 30 is pushed down by the document P2 because a gap between the glass plate 21 and a leading end of the guiding unit 30 in the first state is smaller than the thickness of the document P2. However, even when the gap between the glass plate 21 and the leading end of the guiding unit 30 in the first state is larger than the thickness of the document P2, the guiding unit 30 may be pushed down due to weight of the document P2, for example.

Similarly, it is possible to obtain a strong feeling of bump contact the document transport path T depending on types of originals, when the document is inserted into the document transport path T such that the leading end of the document is brought into abutting contact with the transport roller 11.

In other words, when a document having the high stiffness and the leading end of the document is guided to a document nipping position by the transport roller 11 and the glass plate 21, the leading end of the document pushes up the sensor unit 20. As a result, there is a lack of the feeling of bump contact, and thus the leading end of the document may be inserted to a deep side than the document nipping position by the transport roller 11 and the glass plate 21. However, the guiding unit 30 comes into the second state, and thereby it is possible to obtain the strong feeling of abutting contact of the leading end of the document with the transport roller 11, and thus it is possible to position the document at the appropriate position.

An increase in feeling of bump contact of the leading end of the document with the transport roller 11 means that the leading end of the document comes into belly contact with the transport roller 11. However, even when the thick original is used, and the leading end comes into belly contact with the transport roller 11, the leading end is appropriately guided to a space between the transport roller 11 and the glass plate 21 by rotation of the transport roller 11.

Hence, the scanner 1 according to the present disclosure is suitable for reading both the document thereof (thick original having high stiffness) and the document (thin original having low stiffness) with which abnormal transport occurs due to the belly contact with the transport roller 11.

The guiding unit 30 as described above maintains the first state when the medium P1 (FIG. 9) as an example of a first medium is inserted into the document transport path T and performs switching from the first state to the second state when the document P2 (FIG. 10) as a second medium that is thicker than the first medium is inserted into the document transport path T.

Consequently, there is no need to provide a dedicated unit that switches a state of the guiding unit 30, and thus it is possible to suppress an increase in cost of the apparatus.

The guiding unit 30 may be configured to come into a non-projection state from the lower guide surface 9 b in the second state. Consequently, it is possible to more smoothly obtain the feeling of bump contact when the leading end of the document comes into bump contact with the transport roller 11.

In addition, in the embodiment, the guiding unit 30 is formed to have a size to cover the entire length along the document width direction (X direction) that is a direction intersecting the document transport direction (Y direction) as illustrated in FIG. 11. Consequently, regardless of a size of the document, the leading end of the document inserted into the document transport path T can be guided to the high position on the outer circumferential surface of the transport roller 11, and thus it is possible to more reliably suppress the belly contact of the leading end of the document with the transport roller 11 so as to realize to appropriate transport.

In addition, In the embodiment, the document holding unit that nips the document in cooperation with the transport roller 11 is the sensor unit 20 of which a surface that is brought into contact with the transport roller 11 is configured of a reading surface and which reads the document, and the sensor unit 20 is provided to move toward and back from the transport roller 11. In this manner, the document holding unit is configured of the sensor unit 20, and thereby it is possible to contribute to a reduction in cost and size of the apparatus. In addition, the sensor unit 20 is configured to move toward and back from the transport roller 11, and thus it is possible to read originals having various thicknesses.

The scanner 1 according to the embodiment further has the following features, in addition to features described above. First, the upper housing 4 is provided with a plurality of ribs 4 a on a back side of the upper housing as illustrated in FIG. 16. The ribs 4 a is configured of ribs that are extended mainly along the longitudinal direction (X direction) and ribs that are extended in the document transport direction (Y direction).

In this manner, the plurality of ribs 4 a are formed on a back surface of the upper housing 4, and thereby it is possible to improve stiffness of the upper housing 4 and to smoothly suppress deformation when external pressure is applied.

In addition, the top frame 8 is also provided with similar ribs 8 a as illustrated in FIG. 17, and thereby the stiffness of the top frame 8 is improved, and deformation when the external pressure applied is further suppressed.

In addition, as illustrated in FIG. 15, a connector inserting opening 14 having a coupling unit 15 that is a coupling unit with an external device is formed by the lower housing 3. However, inner walls 3 e, 3 f, 3 g, and 3 h that form the connector inserting opening 14 are provided with a plurality of ribs 3 d that are extended in a connector inserting direction. In FIG. 15, the ribs 3 d formed on the inner wall 3 g and the inner wall 3 h are not illustrated because of an illustrated angle relationship therebetween. However, the inner wall 3 g is provided with the ribs 3 d similarly to the inner wall 3 e, and the inner wall 3 h is provided with the rib 3 d similarly to the inner wall 3 d.

Even when the connector is swayed in a state in which the connector (not illustrated) is inserted, the inner walls 3 e, 3 f, 3 g, and 3 h resists against the swaying with the plurality of ribs 3 d, and it is possible to suppress movement of the connector (not illustrated) to the smallest extent and it is possible to suppress damage to the coupling unit 15.

In addition, holes 3 c and 4 c in FIG. 15 are strap passing holes. However, the hole 3 c and the hole 4 c are formed in the lower housing 3 and the upper housing 4, respectively. Therefore, it is possible to simplify a mold structure more than a case where both of the holes 3 c and 4 c are formed in one housing, and thus it is possible to achieve suppression of an increase in cost.

The battery that is provided in an apparatus bottom portion is also preferably provided in an inclined posture as illustrated in FIG. 18. In FIG. 18, a battery 17A that is provided in the apparatus bottom portion of a scanner 1A is provided in the inclined posture having an inclination angle α with respect to a horizontal plane such that the battery is high on a side of the document insertion opening 5 and is low on a side of the document discharge opening 6. Consequently, it is possible to house a battery as the battery 17A, of which a dimension along the Y direction is long, and thus it is possible to secure battery capacity. A reference sign 24 represents a vibration absorber that is formed of an elastic material such as sponge.

In addition, the scanner 1 includes the control unit (circuit board) 16 (FIG. 5) and the battery 17A on the lower side of the document transport path T, and the sensor unit 20 is provided on the upper side of the document transport path T. Therefore, while a vertical movement range of the sensor unit 20 is secured, it is possible to suppress an increase in size of the entire apparatus.

Subsequently, mainly with reference to FIGS. 13 and 14 and further the other drawings, the document detecting lever 10 as a rotation detecting member will be described in detail.

When a normal posture (posture in which the document transport path T is disposed along the horizontal direction) of the scanner 1 is set as the first posture, the scanner 1 may be used in a posture other than the first posture. Hereinafter, an installation posture (second posture) as an example of the posture of the scanner 1 in which the document transport path T is disposed along a perpendicular direction will be also described.

The document detecting lever 10 that is provided to detect whether the document is inserted from the document insertion opening 5 is configured of a contact detecting unit and is advantageous more than a transmissive or reflective optical sensor in terms of cost suppression or false detection suppression. However, when the posture of the scanner 1 changes, the contact portion 10 b of the document detecting lever 10 retracts from the document transport path T due to action of gravity depending on the posture, and thus a spring force of the coil spring 12 which presses the document detecting lever 10 needs to be determined in consideration for not only one installation posture but also other installation postures.

When a state continues for a long period, in which the coil spring 12 causes the contact portion 10 b of the document detecting lever 10 to project to the document transport path T against a force that causes the contact portion 10 b of the document detecting lever 10 to retract from the document transport path T due to the action of gravity, there is a concern that, as time passes, a balance will be lost between a force by which the contact portion 10 b of the document detecting lever 10 retracts from the document transport path T due to the action of gravity and a force by which the coil spring 12 causes the contact portion 10 b of the document detecting lever 10 to project to the document transport path T, and it is not possible to appropriately maintain the posture of the document detecting lever 10.

In addition, when the spring force of the coil spring 12 increases, there is a concern that a force necessary for the leading end of the document to push up the contact portion 10 b of the document detecting lever 10 will increase, thus, it is not possible for the leading end of the document having the low stiffness to push up the contact portion 10 b of the document detecting lever 10, and jam will occur. When the spring force of the coil spring 12 is set to the minimum necessary degree in order to avoid such a problem, a very delicate balance is kept between the force by which the contact portion 10 b of the document detecting lever 10 retracts from the document transport path T due to the action of gravity and the force by which the coil spring 12 causes the contact portion 10 b of the document detecting lever 10 to project to the document transport path T, and thus the problem described above arises still more easily.

In consideration for the problem described above, the document detecting lever 10 is disposed and configured as will be described below. In the normal posture (first posture) of the scanner 1, the rotary shaft (rotation center) 10 a of the document detecting lever 10 is positioned on the upper side of the document transport path T as illustrated in FIG. 13, the contact portion 10 b projects from the upper side toward the lower side of the document transport path T, and a center-of-gravity position G of the document detecting lever 10 is positioned on the lower side from the rotary shaft (rotation center) 10 a.

Consequently, in the normal posture (first posture), the contact portion 10 b of the document detecting lever 10 is lowered by its own weight without a need for the pressing force of the coil spring 12, and thus it is possible to block the document transport path T.

Therefore, in the normal posture (first posture), that is, the posture that is highly likely to be taken for the longest time of the service life of the apparatus, it is possible to appropriately maintain the posture of the document detecting lever 10 in which the pressing force (spring force) produced by the coil spring 12 does not act against the force by which the document detecting lever 10 retracts from the document transport path T due to the action of gravity. In addition, an unnecessary opposite force does not act on the coil spring 12 in the normal posture (first posture), and thus it is possible to appropriately maintain the spring force of the coil spring 12 over a long period.

In addition, the spring force of the coil spring 12 is set to the extent that it is possible to maintain the state in which the contact portion 10 b blocks the document transport path T, in a case where the posture of the scanner 1 is the second posture in which the document transport path T is disposed along the perpendicular direction as illustrated in FIG. 14.

Specifically, in FIG. 14, a reference sign G represents the center-of-gravity position of the document detecting lever 10, a reference sign W represents a weight of the document detecting lever 10, a reference sign Wr1 represents a component force of the weight W in a rotating direction, a reference sign Rc represents a rotation center position, a reference sign Lg represents a distance between the center-of-gravity position G and the rotation center position Rc, and a reference sign θ represents an angle formed between a direction of gravitational force and rotation moment that acts on the center-of-gravity position G.

In the state in FIG. 14, the minimum torque Tmin necessary for the coil spring 12 to maintain the posture (posture in which the contact portion 10 b blocks the document transport path T) of the document detecting lever 10 can be represented by Expression (A). T min=Lg×Wr1=Lg×W cos θ  (A)

Hence, when rotational torque T that is applied to the document detecting lever 10 by the coil spring 12 is equal to or larger than the minimum torque Tmin, it is possible to maintain the state illustrated in FIG. 14. It is preferable that the spring force of the coil spring 12 be set in consideration for manufacturing variations of the document detecting lever 10, and the rotational torque T be set to a value obtained by adding a predetermined margin to the minimum torque Tmin.

FIG. 13 illustrates a force that acts on the document detecting lever 10 when the scanner 1 is in the normal posture (first posture), in which a reference sign F represents a force by which the leading end of the document pushes the contact portion 10 b at a position S at which the leading end comes into contact with the contact portion 10 b, a reference sign Fr represents a component force of a force F in the rotating direction, and a reference sign Lf represents a distance between the position S and the rotation center Rc. In addition, a reference sign Wr2 represents a component of the weight W in the rotating direction.

It is possible to obtain the minimum value Fmin of the force F, by which the leading end of the document can push up the contact portion 10 b, by Expressions (B), (C), and (D). F min×cos θ=Fr  (B) Fr×Lf=F min×cos θ×Lf≥Wr2×Lg+T min=W sin θ×Lg+T min  (C) F min≥[W sin θ×Lg+T min]/[cos θ×Lf]=[W sin θ×Lg+Lg×W cos θ]/[cos θ×Lf]=[Lg×W×(sin θ+cos θ)]/[cos θ×Lf]  (D)

The minimum value Fmin of the force F, by which the leading end of the document can push up the contact portion 10 b, is preferable to be set to a very small value, in consideration for a state in which it is possible to push up the contact portion 10 b even in a case of the document having the low stiffness. From such a viewpoint, it is preferable to set a size or a material of the document detecting lever 10 or the spring force of the coil spring 12.

In addition, in the embodiment, the center-of-gravity position G is closer to the rotation center position Rc than the position S at which the leading end of the document bumps against the contact portion 10 b. Consequently, it is possible to push up the document detecting lever 10 with a lighter force than that required in a configuration in which the center-of-gravity position G is more separated from the rotation center position Rc than the position S at which the leading end of the document bumps against the contact portion 10 b.

In addition, in the embodiment, the contact portion 10 b is formed along the document width direction (X direction) so as to cover the entire region, through which the document is passable, in the document width direction that is a direction intersecting the document transport direction (refer to FIG. 12), and thus it is possible to detect passing of the document regardless of the size of the document.

In addition, in the embodiment, since the contact portions 10 b are provided at appropriate intervals along the document width direction (X direction) as illustrated in FIG. 12, it is possible to reduce the weight of the document detecting lever 10, and it is possible to push up the document detecting lever 10 with a light force.

The control unit 16 (FIG. 5) can execute an automatic mode for starting driving of the transport roller 11 and reading of the document after a predetermined time after the control unit detects that the leading end of the document rotates the document detecting lever 10 based on a detection signal that is received from the sensor 13 (FIGS. 3 and 4).

To be described more specifically with reference to FIG. 19, when the control unit 16 detects that the leading end of the document passes based on the detection signal that is received from the sensor 13 (Yes in Step S101), the control unit sets waiting for a predetermined time (Step S102). For example, the waiting can be set to one second. When the leading end of the document reaches the nip position between the transport roller 11 and the sensor unit 20 during the waiting for the predetermined time in most cases, and thus the transport of the document, that is, the driving of the transport roller 11, and the reading of the document by the sensor unit 20 are started (Step S103).

Then, rotation correction of read image data is performed (Step S104), and an image of the document is segmented (Step S105). In Steps S104 and S105, image processing is performed.

In the automatic mode, the reading of the document is started before the leading end of the document is nipped between the transport roller 11 and the sensor unit 20, and thus it is possible to avoid missing a part of an image of the leading end of the document.

In the scanner 1 described above, the roller that feeds the document is configured of the single transport roller 11. However, the embodiment is not limited thereto, and a configuration may be employed, in which a plurality of rollers are provided. For example, a configuration may be employed, in which a pair of rollers is provided as a first roller pair, the sensor unit 20 is provided downstream from the first roller pair, and a second roller pair that is a pair of rollers is provided more downstream from the first roller pair. In a case of the configuration, one roller of the first roller pair can be the transport roller 11 according to the embodiment.

In addition, in the embodiment, the document holding unit that holds the document in cooperation with the transport roller 11 is configured of the sensor unit 20. However, the embodiment is not limited thereto, and a configuration may be employed, in which the document holding unit is configured of another member such as a roller as described above.

In addition, in the embodiment, the sensor unit 20 is provided on one side of the document transport path T. However, a configuration may be employed, in which the sensor unit is further provided on the other side and it is possible to read both surfaces of the document.

In addition, a case where characteristic configurations of the scanner 1 described above are described are applied to the scanner as an example of the image reader is described. However, the characteristic configurations can be applied to a recording apparatus represented by a printer, which includes a recording head that performs recording on a medium. 

What is claimed is:
 1. An image reader comprising: a document transport path through which a document to be read is transported; a transport roller that is provided on a lower side of the document transport path and is driven to apply a feed force to the document, wherein the lower side of the document transport path is a side that contacts a bottom surface of the document being transported; a document holding unit that is provided above the transport roller and holds the document in cooperation with the transport roller, wherein the lower side of the document transport path upstream from the transport roller is formed on a lower guide surface that guides the document to the transport roller and is at a position that is lower than a highest position of an outer circumferential surface of the transport roller; and a guiding unit that is provided downstream from the lower guide surface and guides the document from the lower guide surface to a position on the outer circumferential surface of the transport roller, the position on the outer circumferential surface of the transport roller being higher than the lower guide surface.
 2. The image reader according to claim 1, wherein the guiding unit is configured to switch between a first state in which the document is guided to the position on the outer circumferential surface of the transport roller, the position being higher than the lower guide surface, and a second state in which the document is guided to a position that is lower than the position to which the document is guided in the first state.
 3. The image reader according to claim 2, wherein the guiding unit maintains the first state by a pressing force of a pressing unit in a non-transport state of the document, and the guiding unit maintains the first state when a first medium is inserted into the document transport path and performs switching from the first state to the second state when a second medium that is thicker than the first medium is inserted into the document transport path.
 4. The image reader according to claim 2, wherein the guiding unit comes into a non-projection state from the lower guide surface in the second state.
 5. The image reader according to claim 1, wherein the guiding unit is formed to have a size to cover the entire image reader in a document width direction that is a direction intersecting a document transport direction.
 6. The image reader according to claim 1, wherein the document holding unit that nips the document in cooperation with the transport roller is a sensor unit of which a surface that is brought into contact with the transport roller is configured of a reading surface and which reads the document, and the sensor unit is configured to move toward and back from the transport roller.
 7. The image reader according to claim 1, wherein the document transport path is extended along a horizontal direction when the reader has a first posture and includes a rotation-contact member that is provided upstream from the transport roller in the document transport path and rotates to have a posture in which a contact portion that comes into contact with the document blocks the document transport path and a posture in which the contact portion opens the document transport path, a pressing member that presses the rotation-contact member in a direction in which the contact portion blocks the document transport path, and a detecting unit that detects the posture of the rotation-contact member, wherein a rotation center of the rotation-contact member is positioned on an upper side of the document transport path in the first posture and the contact portion projects from the upper side toward the lower side of the document transport path, and a center-of-gravity position of the rotation-contact member is on a lower side from the rotation center in the first posture.
 8. The image reader according to claim 1, wherein a reading position, at which the document is read, is positioned upstream from a rotation center of the transport roller in a transport direction. 